We practically live on this strip of river and my daughter has about 500 miles on Ruby Horsetheif (Loma-Ruby) and she is only 7.
Bring ya some floats, tie them to the raft and float! The winds in July are typically 5-15 mph DOWN river in the mornings, switching like clock work right at 1230 pm to UP river. Near Loma the winds at 3 pm seem to intensify and be almost unbearable. If you are at least near Mee Canyon the winds tend to be more forgiving around 3pm with gust around 15 mph. All in all try and be on the river moving to your next spot by 1030 am and wind shouldn't be an issue.
HEAT: Its hot, but we spend/live in the water most the trip. My wife says she only packs 2 changes of cloths and a bathing suit for the typical 4 day trip. It will be hot, but a quick jump into the refreshing water solves that problem. Zip your tent up good as the afternoon winds will carry sand and find its way into the ole sleeping bag. Never fear, nights cool off quick and by 8:30 Pm will be low 70's or mid 60's.
If you have to travel, like I said....get on the river early. If you launch late....well, try not to get to aggravated at the winds and Shaun, Wayne and Troy (River Rangers) completely understand if you have to find a spot for the night and camp. If you dont make your camp site and do have to find a spot due to winds, try and minimize your impact in that area and they will understand.
Clean up after yourself, have fun and enjoy the beauty of Ruby Horse.